Field of the Invention
The present invention relates to a seal structure for a fuel battery.
Description of the Conventional Art
In the fuel battery, a fuel battery cell is constructed by laminating separators in both sides of a thickness direction of a membrane electrode assembly (MEA) which is provided with a pair of electrode layers in both surfaces of an electrolyte membrane, and the fuel battery is constructed as a stack structure by laminating a lot of fuel battery cells. Further, oxidation gas (air) is supplied to a cathode side of the membrane electrode assembly, fuel gas (hydrogen) is supplied to an anode side of the membrane electrode assembly, and an electric power is generated on the basis of an electrochemical reaction which is a counterreaction of an electrolysis of water, that is, a reaction which creates water from hydrogen and oxygen.
In this kind of fuel battery, a gasket for sealing the fuel gas, the oxidation gas, the water created by the electrochemical reaction mentioned above and the surplus are used in each of the fuel battery cells. More specifically, a gasket 103 made of a rubber-like elastic material (a rubber material or a synthetic resin material having a rubber-like elasticity) is retained to a seal installation groove 101a which is formed in one separator 101 among mutually laminated separators 101 and 102, and a seal protrusion 103a formed in a raised manner in the gasket 103 is brought into close contact with a seal groove 102a which is formed in the other separator 102, for example, as shown in FIG. 7.
In the case that a width of the seal installation groove 101a of the separator 101 is equal to a width of the seal groove 102a of the separator 102, a base portion 103b in a root of the gasket 103 bulges by a stress generated by compression deformation in a thickness direction of the seal protrusion 103a of the gasket 103 in a process of laminating and assembling the separators 101 and 102, and there is a risk that an end portion of the base portion 103b is bitten between groove shoulder portions of the separators 101 and 102.
Further, in order to prevent the end portion from being bitten, there has been known that a width Wb of the seal groove 102a of the separator 102 facing to the gasket 103 is set to be larger than a width Wa of the seal installation groove 101a of the separator 101, such as an example shown in FIG. 7. According to the structure mentioned above, it is possible to inhibit or avoid the end portion of the base portion 103b from being bitten between the groove shoulders of the separators 101 and 102 even if the base portion 103b bulges due to the compression stress of the seal protrusion 103a of the gasket 103 in the process of laminating and assembling the separators 101 and 102 (refer to Japanese Unexamined Patent Publication No. 2009-277957).